High-pressure dome type compressor capable of preventing oil discharge due to gas and of cooling oil by discharge gas

ABSTRACT

A high-pressure dome type compressor is capable of successfully cooling oil fed to sliding portions during a passage of oil in a drive shaft by discharge gas without causing the oil to be discharged along with the gas. In the drive shaft of a motor disposed in a casing and a moveable scroll of a compression section driven by the drive shaft, there are defined discharge gas passages for discharging, into the casing, compressed fluid compressed in a compression chamber of the compression element. An oil feed passage for oil pumped up from an oil reservoir at a bottom of the casing is defined in the drive shaft so as to be partitioned from the discharge gas passage.

This application is the national phase under 35 U.S.C. §371 of prior PCTInternational Application No. PCT/JP 96/02168 which has an Internationalfiling date of Aug. 1, 1996 which designated the United States ofAmerica, the entire contents of which are hereby incorporated byreference.

TECHNICAL FIELD

The present invention relates to a high-pressure dome type compressor inwhich a motor and a compression section to be driven by a drive shaftare disposed within a high-pressure dome type closed casing.

BACKGROUND ART

Conventionally, there has been known a high-pressure dome typecompressor as disclosed in, for example, Japanese Patent Laid-OpenPublication No. SHO 60-224988. In this high-pressure dome typecompressor, a suction pipe is connected to a compression section,compressed gas compressed by the compression section is once dischargedinto the casing and then discharged out of the casing via an outsidedischarge pipe.

More specifically, in the conventional high-pressure dome typecompressor, as shown in FIG. 2, a compression section E comprising afixed scroll B fixed to a housing A disposed in a casing F and a movablescroll D to be driven by a drive shaft C of a motor M is internallyprovided airtight within the closed casing F. A suction pipe G isconnected to the fixed scroll B, and a discharge port H opened into thecasing F is defined in the fixed scroll B.

In the movable scroll D, there is defined a boss D1 to which is fittedan eccentric shaft portion C1 of the drive shaft C that is connected tothe motor M, so that the movable scroll D will be eccentrically rotatedas the drive shaft C rotates. The drive shaft C is supported with abearing by the housing A, while oil in an oil reservoir J at the bottomof the casing F is pumped up through an oil feed passage C2 defined inthe drive shaft C so as to be fed to the bearing portion and boss D1'ssliding portion of the housing A.

Then, gas sucked from the suction pipe G into the compression section Eis compressed in a compression chamber K defined between the scrolls B,D, then discharged into the casing F through the discharge port Hdefined at the center of the fixed scroll B, and thereafter dischargedout of the casing F via an outside discharge pipe L.

For the conventional high-pressure dome type compressor, there is a needof cooling oil because the oil fed to the bearing portion through theoil feed passage C2 of the drive shaft C, which has become high intemperature due to frictional heat, is returned to the oil reservoir Jof the casing F. However, the cooling of oil in the oil reservoir J isusually implemented merely by naturally cooling only the surface of theoil reservoir J by heat exchange with the discharge gas which has beendischarged into the casing F, not by aggressively cooling the oilenough. Thus, there has been a problem in that seizure may occur to thesliding portions.

In operating ranges in which the amount of refrigerant circulationdecreases, there has been another problem that oil cannot be cooled upby discharge gas so that the oil becomes an abnormally high temperature,causing a deterioration of the oil.

As a solution for this, it might be conceived to implement the coolingof oil by aggressively putting the discharge gas into contact with thesurface of the oil reservoir. With this solution applied, however, theoil would be disturbed by the discharge gas being blown against the oilreservoir, resulting in a problem of so-called oil rise that the oil isdischarged along with gas.

The present invention has been developed in view of the above describedproblems and has for its essential object to provide a high-pressuredome type compressor capable of successfully cooling the oil fed tosliding portions by implementing heat exchange between the discharge gasand the oil fed to the sliding portions, without causing any oil rise.

DISCLOSURE OF THE INVENTION

The present invention provides a high-pressure dome type compressor inwhich a compression section having a fixed scroll and a movable scrollas well as a motor having a drive shaft for driving the movable scrollof the compression section are disposed in a closed casing, thehigh-pressure dome type compressor being characterized in that:discharge gas passages for discharging, into the closed casing,compressed gas compressed in a compression chamber of the compressionsection are defined in the movable scroll and the drive shaft,respectively, and an oil feed passage for oil pumped up from an oilreservoir located at a bottom of the closed casing is defined in thedrive shaft so as to be partitioned from the discharge gas passage.

According to the present invention, heat exchange between discharge gasflowing through the discharge gas passage and oil flowing through theoil feed passage is carried out so that the oil within the oil feedpassage to be supplied to the bearing and other sliding portions can besuccessfully cooled by the discharge gas within the discharge gaspassage. Still, since the discharge gas passage and the oil feed passageare defined so as to be partitioned from each other, any disturbance ofoil due to discharge gas can be prevented so that the cooling of oil canbe accomplished successfully without causing any oil rise.

Furthermore, since heat exchange between discharge gas and oil issuccessfully carried out, the temperature difference between dischargegas temperature and oil temperature can be minimized so that the stateof oil can be determined based on the discharge gas temperature. Thus,the control of oil temperature is facilitated.

When a large quantity of refrigerant is mixed in low-temperature oil,for example, at a start of the compressor, the oil within the oil feedpassage can be heated by the discharge gas flowing through the dischargegas passage. Therefore, gas can be separated from the oil by a heatingprocess before the oil is fed to the lubricating portions, so that theviscosity of oil can be increased and thus the lubrication performancecan be improved.

In an embodiment, the discharge gas passage of the drive shaft isprovided so as to be eccentric with respect to an axis of the driveshaft, in an eccentric direction of the movable scroll driven by thedrive shaft.

According to this embodiment, the discharge gas passage is provided insuch a direction that any imbalance of the movable scroll is canceled.Therefore, the balance weight provided to the drive shaft may be smallerthan the conventional, so that the compressor can be designed to belighter in weight.

In an embodiment, a discharge pipe is opened to a first space definedbetween the compression section and the motor while the discharge gaspassage of the drive shaft is opened to a second space defined on a sideof the motor opposite to a side of the motor on which the compressionsection is provided.

According to this embodiment, discharge gas discharged from thedischarge gas passage is discharged out of the casing through thedischarge pipe, after it has cooled the motor. Therefore, the cooling ofthe motor can be aggressively fulfilled by the discharge gas dischargedfrom the discharge gas passage. Still, during the cooling of the motor,oil in the discharge gas is separated so that the oil rise can beprevented more successfully.

Further scope of applicability of the present invention will becomeapparent from the detailed description given hereinafter. However, itshould be understood that the detailed description and specificexamples, while indicating preferred embodiments of the invention, aregiven by way of illustration only, since various changes andmodifications within the spirit and scope of the invention will becomeapparent to those skilled in the art from this detailed description.

The present invention will become more fully understood from thedetailed description given hereinbelow and the accompanying drawingswhich are given by way of illustration only, and thus are not limitativeof the present invention, and wherein:

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a longitudinal sectional view of one embodiment of thehigh-pressure dome type compressor according to a present invention; and

FIG. 2 is a sectional view showing a conventional high-pressure dometype compressor.

BEST MODE FOR CARRYING OUT THE INVENTION

FIG. 1 is a high-pressure dome type scroll compressor showing anembodiment of the present invention. In the scroll compressor, a housing2 is fixed to a closed casing 1, a compression section CF is disposedabove the housing 2, and a fixed scroll 3 of the compression section CFis fixed to the housing 2. On the other hand, a motor M for driving thecompression section CF is disposed below the housing 2, and a driveshaft 4 of the motor M is held to a bearing portion 21 of the housing 2.

Further, the housing 2 serves for the partition into a low-pressure sidechamber 5 where the compression section CF is disposed and ahigh-pressure side chamber 6 where the motor M is disposed and adischarge pipe 11 is opened so that compressed gas compressed by thecompression section CF is discharged. A suction pipe 12 connectsdirectly with the fixed scroll 3. The high-pressure side chamber 6 isdivided into a first space 61 defined by the motor M between the motor Mand the compression section CF, a second space 62 defined by the motor Mand a cup-like pump housing 13 on a side of the motor M opposite to aside of the motor M on which the compression section is provided, and athird space 63 having an oil reservoir 14 and defined below the pumphousing 13.

The compression section CF comprises a movable scroll 7 which has aspiral member 72 protrudingly provided to an end plate 71 and which isconnected to the drive shaft 4 of the motor M, and the fixed scroll 3which has a spiral member 32 protrudingly provided to an end plate 31.These scrolls 7, 3 are oppositely provided so that their spiral members72, 32 engage each other, where a compression chamber 15 is definedbetween the spiral members 72, 32.

In the movable scroll 7, a discharge port 73 for discharging compressedgas compressed in the compression chamber 15 is defined at a centralportion of the end plate 71 of the movable scroll 7, while a cylindricalportion 75 having a discharge gas passage 74 to which the discharge port73 opens is provided to a rear-side central portion of the end plate 71.

In the drive shaft 4, an eccentric boss 41 for receiving the cylindricalportion 75 of the movable scroll 7 is defined, while further providedare a discharge gas passage 42 one end of which is communicated with thedischarge gas passage 74 of the cylindrical portion 75 via acommunicating member 8 and the other end of which is opened to thesecond space 62 defined on the underside of the motor M in the closedcasing 1, and an oil feed passage 43 one end of which is opened into theeccentric boss 41 and the other end of which is communicated with theoil reservoir 14 provided at the bottom of the casing 1 via an oil pump16. The discharge gas passage 42 and the oil feed passage 43 arepartitioned and defined in parallel to each other. This discharge gaspassage 42 is communicated with the second space 62 through an unshownhole.

The communicating member 8 comprises a seal member 82 which isinsertionally fitted into the cylindrical portion 75 of the movablescroll 7 so as to be unrotatable and axially movable relative to thecylindrical portion 75 via a ring seal 81, and a sliding bushing 83which will slide in contact with the seal member 82 and which is pressedand secured into the eccentric boss 41 of the drive shaft 4. Between theseal member 82 and the cylindrical portion 75, there is interposed acoil spring 84 for urging the seal member 82 against the sliding bushing83, by which the seal member 82 and the sliding bushing 83 are sealedfrom each other so that the gas within the discharge gas passages 74, 42will not leak into the eccentric boss 41.

The drive shaft 4 is supported at its lower side by the pump housing 13.The oil pump 16 is a positive displacement type oil pump.

The discharge gas passage 42 formed in the drive shaft 4 is made largerin diameter than the oil feed passage 43, and provided so as to beeccentric with the axis of the drive shaft 4 in the eccentric directionof the movable scroll 7.

Between the movable scroll 7 and the housing 2, an Oldham's ring 17 isprovided so that the movable scroll 7 is enabled to orbit withoutrotating itself.

Further, the rear side of the end plate 71 of the movable scroll 7 issupported by an annular thrust receiving portion 22 defined in thehousing 2. The thrust receiving portion 22 is located inner than theOldham's ring 17. At the inner radius of the thrust receiving portion22, a cylindrical seal ring 18 is further provided to contact with theend plate 71 of the movable scroll 7. By the seal ring 18, a spatialportion defined on the inner radius side of the seal ring 18 ispartitioned from the low-pressure side chamber 5.

Oil pumped up through the oil feed passage 43 is once pumped up into theeccentric boss 41, lubricating a bearing 91 provided between the outercircumferential surface of the cylindrical portion 75 of the movablescroll 7 and the inner circumferential surface of the eccentric boss 41,as well as the bearing portion 21 supporting the outer circumferentialsurface of the eccentric boss 41, while the oil is fed also to the placewhere the seal ring 18 is provided. The oil after effecting thelubrication is returned to the bottom oil reservoir 14 through an oilpassage 19 defined on the periphery of the motor M, via an oil returnpassage 23 formed in the housing 2.

By the movable scroll 7 being driven to orbitally revolve relative tothe fixed scroll 3, the volume of the compression chamber 15 definedbetween the spiral members 32, 72 is varied, by which low-pressure gassucked in through the suction pipe 12 connected to the fixed scroll 3through the casing 1 is introduced between the spiral members 32, 72,and compressed in the compression chamber 15. Then, high-pressure gasdischarged through the discharge port 73 of the movable scroll 7 intothe discharge gas passage 74 of the cylindrical portion 75 is fed to thedischarge gas passage 42 of the drive shaft 4, and thereafter dischargedto the second space 62 through an unshown hole. The gas is furtherpassed through an air gap 10 of the motor M so as to be fed to the firstspace 61, and thereafter discharged out of the casing 1 via thedischarge pipe 11.

With the construction described above, in this embodiment, the driveshaft 4 of the motor M disposed within the closed casing 1 of ahigh-pressure dome, and the movable scroll 7 of the compression sectionCF to be driven by the drive shaft 4 are provided with the discharge gaspassages 74, 42 for discharging, into the casing 1, compressed fluidcompressed in the compression chamber 15 of the compression section CF,while the oil feed passage 43 for oil pumped up from the oil reservoir14 at the bottom of the casing 1 is defined in the drive shaft 4 so asto be partitioned from the discharge gas passage 42. Therefore, heatexchange between discharge gas flowing through the discharge gas passage42 and oil flowing through the oil feed passage 43 is carried out sothat the oil within the oil feed passage 43 to be fed to the slidingportions such as the bearings 21, 91 can be successfully cooled by thedischarge gas within the discharge gas passage 42. Still, since thedischarge gas passage 42 and the oil feed passage 43 are defined so asto be partitioned from each other, any disturbance of oil due todischarge gas can be prevented so that the cooling of oil can beaccomplished successfully without causing any oil rise.

Further, since heat exchange between discharge gas and oil issuccessfully carried out, the temperature difference between dischargegas temperature and oil temperature can be minimized so that the stateof oil can be determined based on the discharge gas temperature. Thus,the control of oil temperature is facilitated.

When a large quantity of refrigerant is mixed in low-temperature oil,for example, at a start of the compressor, the oil within the oil feedpassage 43 is heated by the discharge gas flowing through the dischargegas passage 42. Therefore, gas can be separated from the oil by aheating process before the oil is fed to the lubricating portions, sothat the viscosity of oil can be increased and thus the lubricationperformance can be increased.

Further, the discharge gas passage 42 is provided so as to be eccentricwith respect to the axis of the drive shaft 4, in the eccentricdirection of the movable scroll 7. Accordingly, in this case, thedischarge gas passage 42 is provided in such a direction that anyimbalance of the movable scroll 7 is canceled. Therefore, the balanceweight provided to the drive shaft 4 may be smaller than theconventional, so that the compressor can be designed to be lighter inweight.

Further, the discharge pipe 11 is opened to the first space 61 definedbetween the compression section CF and the motor M, while the dischargegas passage 42 is opened to the second space 62 defined on a side of themotor M opposite to the side on which the compression section isprovided. Therefore, before discharge gas discharged from the dischargegas passage 42 is discharged out of the casing 1 through the dischargepipe 11, the discharge gas is passed through the air gap 10 of the motorM so that the motor M can be cooled aggressively. Still, the oil in thedischarge gas can be separated by the cooling of the motor M, so thatthe oil rise can be prevented further successfully.

Also since the compression section CF is disposed in the low-pressureside chamber 5, the whole compression section CF is thermally insulatedby the low-pressure gas so that suctional overheating is prevented.Thus, a high volumetric efficiency is attained.

INDUSTRIAL FIELD OF APPLICATION

The high-pressure dome type compressor of the present invention is usedfor refrigerators, air conditioners, and the like.

The invention being thus described, it will be obvious that the same maybe varied in many ways. Such variations are not to be regarded as adeparture from the spirit and scope of the invention, and all suchmodifications as would be obvious to one skilled in the art are intendedto be included within the scope of the following claims.

What is claimed is:
 1. A high-pressure dome type compressor in which acompression section having a fixed scroll and a movable scroll as wellas a motor having a drive shaft for driving the movable scroll of thecompression section are disposed in a closed casing,comprising:discharge gas passages for discharging, into the closedcasing compressed gas compressed in a compression chamber of thecompression section are defined in the movable scroll and the driveshaft, respectively, and an oil feed passage for oil pumped up from anoil reservoir located at a bottom of the closed casing is defined in thedrive shaft so as to be partitioned from the discharge gas passage, saidoil feed passage extending generally along an entire length of saiddrive shaft.
 2. The high-pressure dome type compressor as claimed inclaim 1, wherein the discharge gas passage of the draft shaft isprovided so as to be eccentric with respect to an axis of the driveshaft in an eccentric direction of the movable scroll driven by thedrive shaft.
 3. The high-pressure dome type compressor as claimed inclaim 1, wherein a discharge pipe is opened to a first space definedbetween the compression section and the motor while the discharge gaspassage of the drive shaft is opened to a second space defined on a sideof the motor opposite to a side of the motor on which the compressionsection is provided.
 4. The high-pressure dome type compressor asclaimed in claim 2, wherein a discharge pipe is opened to a first spacedefined between the compression section and the motor while thedischarge gas passage of the drive shaft is opened to a second spacedefined on a side of the motor opposite to a side of the motor on whichthe compression section is provided.
 5. The high-pressure dome typecompressor as claimed in claim 1, wherein said oil feed passage extendsin parallel to said discharge gas passages.
 6. The high-pressure dometype compressor as claimed in claim 1, further comprising acommunicating member located between the discharge gas passage definedin the movable scroll and the discharge gas passage defined in the driveshaft, said communicating member for communicating the discharge gaspassages to each other.
 7. The high-pressure dome type compressor asclaimed in claim 6, said communicating member further comprising:a sealmember; a sliding bushing for sliding in contract with said seal member;and a coil spring for urging the seal member against the slidingbushing.
 8. The high-pressure dome type compressor as claimed in claim1, further comprising an oil pump for positively pumping oil from theoil reservoir to the oil feed passage.
 9. The high-pressure dome typecompressor as claimed in claim 1, wherein said compression section islocated at a side of said closed casing opposite to said oil reservoir.